Integrated circuits (ICs) are fabricated on wafers of silicon. Various structures, such as ball grid arrays (BGAs) or wire frames, are utilized to connect the microcircuits fabricated on the silicon to the metallic traces on a printed circuit board (PCB) to form an IC package.
The interconnect circuitry of a IC package is a complicated physical structure that must be tested for reliability prior to verification of the IC package. Testing is usually performed on a sample set of the manufactured IC packages and if a statistically significant number of samples are found to be reliable then the IC package is verified.
One technique of testing IC package reliability is to manufacture specially configured IC packages having metallization traces bridging package substrate traces to create electrical connections between pairs of BGA balls or wire frames. Such specially created IC packages are known as daisy-chained devices.
The daisy-chained device can be tested utilizing an Automatic Electrical Tester (ATE) to verify the reliability of the IC package.